Interlocking key assembly



June 16,1931. P. P. HORN] INTERLOCKING KEY ASSEMBLY Filed Jan. 27, 1928 INVENTOR Patented June 1 6, 193 1 UNITED STATES PATENT OFFICE PAUL P. HORNI, F NEWARK, NEW JERSEY INTERLOCKING KEY ASSEMBLY Application filed January 27; 1928. Serial No. 250,020.

' This invention relates to an assembly of in the instance shown is in the,o n posikeys that is provided with interlocking tion, although it might also be in t e closed means to insure against operating the keys position. The contacts are shown at 9. At in any way that would cause contradictory is shown an interlocking bar which is held results. in a retracted position by a spring 11. This a When a series of keys is associated together bar is supported on guides 12 and has a certain on a keyboard for example, it becomes desiramount of end play thereon. Switches 2 to able to provide means whereby only one key 6 inclusive are provided with notches 13 atatime canbe made to function. When two which,- when any switch is depressed, en'

10 or more keys are simultaneously operated, gages with the interlocking bar 10 and holds they might produce contradictory results or that switch in the contact-making position. I interfere in some way or other with their pro Each of the switches 1 t0 6 is also provided ducing their destined function. with a cam 14 which operates upon the de- One use to which such apparatus may be pression of any swltch topush the interlockapplied is to control circuits used for operating bar 10 against the effect of the spring 11 ing signals such as for example traflic signals to a position that will release any switch held or signals for conveying information by signs down by the interlocking bar. The switch or lights from or :to ,a moving vehicle. In 1 is solely for this purpose'and does not 0psuch case, it is desirable that the operation of erate to make any contacts but simply is a 20 any key to set a given signal shall not funcrelease switch for throwing out of action tion in any way to give a signal that will be any switch that may be closed without at the contradictory to signals already set. A par same time closing any contacts; In order to ticular object of this invention is to provide prevent absolutely the simultaneous operameans whereby the operation of any key to tion of any two or more of the switches, I

,5 set any signal will automatically releaseany provide interlocking plates 15 of which four signal inconsistent with it. are shown, two upper ones and two lower A further object of the invention is to preones. Each of the switches has key bars 16 vent the functioning of two or. more keys of various lateral widths, one width for each when by error or design an attempt is made of the plates 15, which operate in such a way so to operate them simultaneously. The inventhat when a switch is depressed the plates g tion comprises a combination of a plurality will be so arranged that side bars or wings 17 of keys and interlockin mechanism that will on the particular switch being depressed will accomplish the above 0 jects. pass through slots 18 on the plates. When In the accompanying drawings a specific any switch is thus depressed, the plates will embodiment of my invention is S wn as pbe so shifted transversely that theside wings as plied to electric switches for operating traf- 17 on any th k 111 t i t ith fie slgnalsg the slots 18 in its particular location and 212 drilwmgsi therefore such other switch cannot be de- 40 Flgure 1 1S l fi l Sectlon through pressed. The plates 16 are beveled on the the i f th 1 ki lower ends as shown so as to act as cams Flgure 2 1S Plan w 0 e Inter 00 in shifting the plates. Springs 19 serve to hold the interlocking plates 15 in a retracted bars.

Flgure 3 1s perspectwe new of an mdl' position and supports 20 hold the plates with a certain amount of longitudinal play. It 95 vidualized key and its corresponding interlocking plates.

R f i t th d in 1 t 6 repre is evident that the switches may be either sent manually operatable members which in h 111 the c0I 1tact'makmg p f PS the this case are switches which may be assemt hes 13 or in case of closed circuit sysbled in a suitable casing 7. Each switch has te'ms they might be held 1n the open circuit v a spring 8 for holding it in one position which positions.

- 8,11 and 19, gravity or an other force may 3 It is evident also that instead of springs be used to retract the switc es.

While I have shown the application of the invention to the particular case of a multiple switch for controlling traflic signals, the principle of the invention may be equally well applied to any system of manually operatable members assembled together to produce a variety of results.

1. An interlocking key assembly comprising a plurality of manually operatable members, each tendin to assume the open position, an interlocking bar engaging a plurality of the members, means on each of said members for shifting the interlocking bar to a different position when a member is closed from the position that it would be placed by the operation of an other of said members, and means on, eac permitting the closure of only'one of said members at a time by said interlocking bar.

2. A construction according to claim 1 in which a plurality of interlocking bars are combined with a plurality of bar operating keyhars on the members to produce separate combinations of relative position of the bars for each member when operated.

3. A construction according to claim 1 in .which a plurality of interlocking bars are combined with a plurality of bar operating keybars on the members to produce separate combinations of relative position of the bars for each member when operated, with means on each member reventing its arrival at its functioning position when the bars are set by anyiother member.

4. An interlocking key assembly comprismg a plurality of manually operatable key members, each tendin to assumethe open position, an interlocking bar engaging all the, members, the key members beingpro vided with beveled key bars of various widths and the interlocking bar being movable transversely by the key members and having slotted openings through'which the said key bars are adapted to pass, each key member when depressed setting the interlocking bar to a position permitting only such operating key to pass to its depressed position.

. PAUL P. HORNI.

member for 

